Barometric control of time-actuator



Oct. 10, 1950 w. H. KuNTz BAROMETRIC jcoNTRoL oF TIMEAcTuAToRs 2 Sheets-Sheet l `Filed aan. 14, 195o zzz a /4 a m I T mf? N. @am www /A WCW Oct. 10, 1950 w. H. KUN-rz 2,525,508

BARQMETRIC CONTROL op TmE-AcTUAToRs Filed Jan? l14, 195o 2 sheets-sheet 2 Patented ct. O, 1.95:()

BAROMETRIC coNTRoi. F 'rnvrE-ACTUATOR William H. Kuntz, Dayton, Ohio Application January 14, 1950, Serial No. 138,550

11 Claims.

This invention relates to a timer-actuator for setting into action a mechanism to perform a definite act at a predetermined interval of time after an intended initiation, and contemplates an additional control device for a timer-actuator device of the type disclosed and claimed in my copending application Ser. No. 66,309, filed December 20, 1948. The additional control device comprehends a barometric unit mounted within a timer actuator casing and coupled with a tripping element thereof in such manner that the final release of the driving or power dev-eloping means for actuating a selected device, is delayed until preselected conditions are experienced. The barometric control unit is a complete subassembly that fits within the timer-actuator housing and when s-ecured in place is so mechanically coupled with the trip pin and the escapement means of the timer mechanism that the power developing means is restrained from operating, even though the trip pin is withdrawn, until a preselected set of conditions occur. Making toward that end the barometric unit has its own frame enclosing an expansible chamber whose movable Wall carries a cam settable to dilerent positions corresponding to different pressures in terms of altitude and acting as a variable detent obstructing one end of a pivoted lever having a part interposed between the release pin and an extension. of an escapement. The enclosing housing has a cutaway or opening that gives access to the barometric unit for adjustment, and a removable cap seats against the housing to seal and protect against the elements. When the barometric control unit is applied to the timer-actuator referred to and the timer-actuator is attached to a parachute or the like, the time for removal of the trip pin becomes less critical since the barometric control determines that the timer-actuator cannot be started above a certain altitude that has been earlier selected. As an example, the trip pin might be withdrawn by a static line `when the vice, the sealing cap being removed to show the means for setting to desired conditions of operation.

Fig. 2 is a longitudinal sectional view of Fig. 1 substantially as indicated by the line andarrows 2 2.

Fig. 3 is a plan view of the timer-actuator with the cover and additional control unit removed, parts being broken away to better illustrate the relation of certain parts, the view being taken along the line and in the direction of the arrows 3 3 of Fig. 2.

Fig. 4 is an enlarged elevational view of the additional control unit substantially as indicated by the arrow 4 in Fig. 2.

Fig. 5 is a sectional view on a large scale through the base of the additional control unit showing details of the pivot for the release arm, the View being somewhat as indicated by the line and arrows 5 5 of Fig. 4 and Fig. 7.

Fig. 6 is a transverse enlarged sectional'view through the additional control and part of the instrument casing substantially as it would` appear if taken along th-e line and in the direction of the arrows 2 6 in Fig. 7.

Fig. 7 is an enlarged view in plan of the supporting member for the barometric unit` and showing the relation of the control cam and the release lever with respect to the trip pin and the escape mechanism.

Fig. 8 is an enlarged view in end elevation substantially as indicated by the arrow 8 in Fig. 7.

Fig. 9 is a sectional view through the top of the barometric unit and casing cap substantially as indicated by the line and arrows 9 9 of Fig. 6.

Referring to the drawings in detail, and i'lrst with respect to Figs. 1 to 3, the numeral i0 indicates a housing member in the form of a metal box having one open side to be closed by a plate' l2 cooperating with the bottom of the housing to provide journals or bearings for the gearing of the timer-actuator. The gearing comprises a spring motor I4 made up of a shaft I6 secured to a spring enclosing drum IB and a sleeve 20 relatively rotatable about the shaft l and within the plate I2. The shaft I 6 is rotatable in a pocket or recess 22 of the housing. A spiral spring 24 isf` 32 rotatable on the extended end of the shaft I6. The lock disc 3 is notched to receive the lug end of a spring urged lock lever 34 pivoted in the housing members by a shaft 36. The spool 32 has its lower ange notched at 3B to be engaged by the hook end of a retaining lever i0 secured on a shaft or pivot 42. A tail lever d@ joining the lever All is disposed to engage a cam surface of a lever 46 journalled at 48 in the housing members. A lever 59 secured to the same shaft d8 has one end riding on the side of the spring drum and is adapted to drop into a slot 52 when the spring 2li is wound up as shown in Fig. 3. A spring 513 anm ohored to the lever lil has a stressed arm 56 bearing against the lever 46 and tends to project the hook end of lever 4i] into one of the notches 38 of the cable spool, when the end of the lever 5e is riding on the outside of the drum i8.

The upper end of the shaft i@ is squared olii at 5S for reception of a winding key and rotatably supports a knob Bil secured to a plate 62 that has a depending stem Efiwithareduced portion like a pin iifpassing'by the'edge o1" the spool 32, the lock disc Sil and extending through an arcuate slot 6G and selectively engaged in any one of a r'ow o'f holes '|2- of a driving gear li'within the housing members and rotatably disposed about the sleeve 20 between the spring drum |3 and the plate i2. A spring 'i6 disposed between a cover Band the plate 62- keeps the pin S8 in the hole selectedV andtends to maintain the driving relation between the sleeve 2li-'and the spool 32. The driving gear '54. has'ratcheting engagement with the top of the spring drum i3 at 3U, and engages a pinion 82 integral witha largergear 8f3, meshing in engagement with' the teeth oi the escapement gear In the timer-actuator above referred'to,

the arresting oi the e'scapement lever is yaccome plished' by a removable trip pin @S engaging the lug E''that was pulled away when it was desired to set the timer mechanism operating. in the improved" control' here disclosed; a, member 23 is interposed between the pin St and lug 92. The member is'controlled by the barometric unit referred toas will presently be explained.

If the es'capement lever is arrested, then the whole gear train is held against movement so that Athe spring motor I@ may be wound up. W hen unwound the spring 2i! lays against the inside of the spring drum i8 and holds the lever 513 outward so that the shaft dii is rotated clockwise to'osoillate the cam lever 46 clockwise toward the lever iii so 4that the hook end thereof is urged into one of the'notches 3B of the spool 32'. That prevents counterclockwise rotation ofthe spool 32. The cable |69 cannot be fully wound up. Prior to winding the spring 2d the selector knob @d is actuated to set the pin t3 in one of the holes d or 'B2b of the driving gear M. That selecting removes the depending portion @f3 from engaging relation with the spring urged lock lever 3d so that .its end can drop into a, notch of the lock plate which prevents the plate and attached sleeve 2S attached'to the end oi the spring from turning in a clockwise direction. Under those conditions rotating thn shaft it by means of an appropriate key, rotates the spring drum I8 which ratchets over the provisions 8G and with respect to the driving gear E8 which is held against movement by the pin 96. When the spring is fully wound up, the outermost turn is retracted from the inside of the drum so that the lever 50 is urged through slet 52. That is by reason of the spring ed which rocks the cam lever 6.6 that results in oscillating the lever 43 away from the spool notches 38. That permits'the cable |00 to be pulled out and attached to the device to be actuated. Thus it is insured that the power developing means must be conditioned for operating the device before the actuating cable can be attached, a very important safety feature. The timer-actuator is now normally ready for operation when the release pin 96 is removed. However, the interposed member 98 is still in position to prevent start of the time measuring device.

The interposed member 98 is in the form of a lug on an oscillating lever |62 and controlled by theA additional control-unit! |04! enclosed within the timer-actuator unit, and illustrated Vin Figs. 4 to 8-inclusive- Theunit comprises a sub-base i96- adapted to mount vagainst the top-of the mounting plate i2l at one end' ofY the'instrument housingas shown in Fig. 2; The'sub-base has a pair of spacingribs |8 along each endandon top of which thereismounted a U-shapedlbracket member Iii by rivetsll i2, having shimsA l Hand H6 disposed between the` ribs Hi8 andL bracket member ili; Theishim |.|4 has a lateral flexible extension i ESithat projects'toione'side ofthe associated rib |08 as shown lin-Fig. 'TQ-where it is exposed through a key-hole. shapedV cut-out vIiZ which has-a circular portionV I-ZZLand/a peripheraily joined rectangularportiony |24. The extension H8 projects nearly across-.the-opening |24 and provides an. opening |26` disposed `over an aligned aperture- I in the sub-base ILIG; Those apertures Mii-and` |253l provide bearings for the conical points |36` and |327' respectively of a shaft i3d' rig-idlyv mounted in the oscillating lever H32,V be'iore'reierred to. The extension H8 ispreflexed toward the sub-base HiB-so that when the shaft i3d-is mounted with theV conical ends |33; |32A disposed in the apertures |26, |28-, the lever |62 will be heldiirmly in its pivots or bearings without wobble orlost motion. The lever |2fwhen`assembledinl place has its lug 98V forming the beforeY mentioned interposed member which vextends through an aperture Vlig to span the distance between vthe pin gffand the'lug S2 4when the escapement-lever 9B is locked'against movement, as it isi-shown in Fig. 3. Theplate l2 is similarly notched or aperturedto coincideY with the. aperture i315, (though not shown) to permit oscillation of the luge@ when the pin 96 is removed. Theopposite end ofthe lever |'l2 is shaped to provide an arm i3d extending intorthe circular portion M2V of the cutout,V and upwardlyto point above the plane of the bracket member |`il` to end in a pointv or detent |110. Oscillation of the lever D62 is conditionally restrained by a web or cam flange |42 extendingfromja disc Nfl-.carried by themovable wall l'liii`y of an aneroid or barometric unit rotatablyV mounted on an inverted U- shaped bracket member |48 whose parallel flanges |58 telescope within the parallel flanges |52 of the bracket lill'f to be rigidly united by rivets or .the like |54, substantially asshown in Fig. 6.: Rotatable in thecenter of. the bracket there is a plug |56 to which i'sanchored a sylphon or bellows head member' it, this head' member being circular and substantially the same diameter as 1 teams the.' |46.' lA cylindrical bellows or flexible wall `tubular element |60 has each end `flange/secured to the `head member |43 and the movable wall |46 to enclose an expanding spring |62`under stress tending to separate the members |46 and |43. A tubular stem |64 extends through the disc |44 andthe movable wall |46 by which the "interior of the Sylphon is evacuated and sealed by closing at |66. All joints of partsl makingfup the aneroid unit, such as the movable wall |46, the plug |56, the head member |56, the bellows |60 and the stem |64, are sealed by soldering or bonding to make the unit air tight. i

The -aneroid unit is supported by the top bracket.|48 `with the plug |56 capable of limited rotation in the bracket by reason of a` radial key |63 on the periphery of the plug traversing a notch in the bracket `adjacent the journal -for the plug. A shim |70 surrounds the plug |56 and rests against the upper surface of the bracket |43, the shim HB being bevelled at the outer edge to carry an index arrow as shown in Fig. l, and also having la, notch engaged by; the key |63lso that the shim will be rotated with the aneroid unit whenever the plug |56 is turned.

bracket |48 is against the top of the Sylphon head |58, a dished spring washer |l2 is fitted over a reduced portion of the plug |56 and engages the shim |70 where it is held under stress by a spring ring |14 disposed in a peripheral groove about the reduced portion of the plug, such as is shown in Figs. 6 and 9. The Sylphon unit is thereby frictionally retained in any angular position with respect to the bracket |48 to which it is turned by the plug |56, a notch or screw-driver slot |16 being provided on the outer end of the plug to assist in that turning. A scale ITB, calibrated in thousands of feet altitude, being marked on the upper surface of the bracket |48 adjacent the before mentioned arrow, assists in indicating the rotative position of the` plug.

Rotation of the plug |56 also rotates the aneroid unit and cam flange |ll2 attached to it.

When the additional control unit is properly assembled, the 'cam flange |22 will be disposed over the cut-out |22 of the lower bracket and will be suspended above the detent or point |40 of the lever |02. The cam iiange |42 is arcuate and concentric about the axis of the plug |56 ending with an incline surface |80 cooperable with the detent |40 of'said lever. Obviously, if the aneroid unit is rotated to different angular positions, there will be required different degrees of collapse of the capsule before the lever |02 can be oscillated without the point |40 being obstructed by the cam flange |42. The cam ange |42 and detent |40 are so related and associated that when the point or detent |40 is bearing against the inside of the cam nange |22 as shown in Fig.

7, then the interposed member 98 on theother end of the lever will be properly disposed to ll all the space between the release pin 96 and the lug 92 of the escapement lever.` It therefore necessitates that the cam flange |42 be withdrawn from its obstructing position before the lever |02 can oscillate away from the lug 92.

The additional control unit |64 as shown in Figs. 4 and 6 `is mounted against the plate I2 of Ythe timer-actuator as shown in Fig. 2, there being holes |32 in the corners of the sub-base |06 that are aligned with similar holes |23 in the corners of the `plate I2, and that are also aligned withthreaded holes in corner bosses lil/i of the housing member I0. Spacers |66 are disposed To maintain A the Vaneroid unit firmly in place so that the upper betweenthe cover 18 and the sub-base |06l so that screws |86 when threaded into the corner bosses |84 will hold the cover and additional control unit i'lrmly in place. A cable clamp |90 has a iiange |92 apertured to receive the screws |88 and unites with a clip |94 to anchora flexible conduit ISE which encloses and guides the release pin 0 6. A second cable clamp |98 at the other end of the cover 'i8 cooperates with a clip 200 to anchor a flexible conduit 202 enclosing the actuator cable |00 in a similar manner.

The cover 'I8 carries a number of headed pins 204 that cooperate with keyhole slots 206 in a cup-like member 208 used to enclose and seal over the setting knob 6i) `as described in the aforementioned application. 'Ihe cover 18` is apertured at 2||l with winged extensions 2|2 that is disposed directly over the plug |56 of the additional control unit.` The aperture 2 0 gives access to the` plug |56` for adjusting to the altitude `at which the arm |22 will be permitted to release the timerjmechanism, which altitude is indicated by the scale |158 on the top of the bracket member |46 and observable through one of the winged extensions 2.!2. The portions of the cover 18 bounding the aperture 2li] and between the winged extensions`2|2 are bent upward and inwardly as indicated at 2|4 to provide locking cams cooperating with a bar 2|6 secured inside of a cap 2|8 carrying a Seal ring 220 engageable with the cover 18 as shown in Figs. 6 and 9. The caps 208 and 2|8 together with their respective seals protect the working mechanisms within the housing and cover from moisture and foreign matter that might interfere with the properoperation of that timer-actuator.

For mountingthe timer-actuator, the housing I0 has tongue-like members 222 and 224 at opposite ends that engage beneath arched loops 226 and 220 provided by a mounting plate 230 where it is secured by a holding screw 232, the overall length of the housing |0 being so much less than the distance between the loops 226 and 228 that the tongue 22d may be insertedbeneath the loop 222` `and slid within it far enough for the end of the tongue 222-to move laterally past the near edge of the loop 226 and then slide beneath it before the tongue 221il is withdrawn from the loop.

With both of the tongues beneath their respec-` tive loops, then the screw 232 may be threaded into place to secure the unit in the proper mounted position. `The mounting plate 230 provides holes 204 in each corner that makes for the use of rivets,screws `or bolts by which the unit may be secured to a package or the like, while the smaller holes 236 adapt the use of thread, string,

wire or thongs by which the mounting plate may be laced or sewed` in place to clothing or to a parachute harness, or toY a cloth or fabric wrapper of a parcel. To prepare the apparatus for use, assurnin that itis coupled to the mounting plate that is installed for actuating a, device by a pull or tug upon the-cable |00, the first thing done is to insert the release or trip pin 96 which strikes the slanting surface of thelug 98 and biases it against the lug Q2 of the escapement lever 90.` The biasing of the lever |02 rocks it clockwise about the pivot |26 as viewed in Fig, 7, during which, the detent |40 rocks inward of the cam flange |42, After inserting the trip pin S6 and arresting operation of f the escapement mechanisrn, the knob 60 is raised and turned slightly clockwise from the position adjacent the lock lever S4 which allowsthe lever to lock the dise` for holding the innerY end of the spring s ub-.-

stantially xed. The cable |00 beingV wound upon the spool, the outermost leaf of the spring 24. willlay against the inside of the drum |8 so that the lever 50 rocks the, cam lever 4,6 clockwise to bias the safety lever into engagement with device, since the inner end of the spring 24 isl held against movement by the lock lever 34, disc 30, and sleeve shaft 20, to which the inner end of the spring is fastened. The trip pin 96 being in place, the gear train oi the escapement mechanism is held against movement While rotation of the shaft I6 drives the spring housing |8 and causes it` to ratchet over the tongues at 80 which are held against movement by the release pin 9B holding the gear train inactive.

Complete winding of the spring 24 by rotation of the shaft |6 causes the outside turn of the spring to retract from the inside of the spring housing to uncover the opening 52. The lever V may now cscillate to a position extending within the housing i8 through the opening 52 substantially as shown in Fig. 3. The shaft 48 thereby rotates to oscillate the cam lever 46 counterclockwise, which rocks the lever 40 clockwise away from the spool ange 32 and therefore disengages the notches 38. The spool 32 isnow capable of rotation for withdrawing the cable |00 which is done by pulling upward on the knob to disengage the driving provisions 26 and permit the spool to ratchet over beveled portion 2B. While the knob 60 is in this outward position it is, or may be, turned to spot the pin 68 in the proper one of the time designating holes 'i2 for which the actuator is to operate after escapement release by the trip pin 96.

By selected setting of the pin 68 in one or another of the time designating holes '|2 the unit may be made to set off actuation of the cable` |00. either substantially coincident with removal of the trip pin 96, or at the elapse of a denite period oitime after removal of the trip pin.

On the other hand, actuation of the cable |00 I may be in accordance with other factors, such as the additional control by means of the aneroid unit. If operation is desired after that last mode of control, the cable will then be actuatedsubstantially at the instant of release, not bythe removal of theV trip pin 96, but by the disengagement ofthe detent |40 andcam flange |42. Also, the actuation may be at the end of a measured interval of time after that disengagement. Obviously, if each or the holes '|2 standz for aodifferent time interval, and are spaced one or two seconds apart, then a setting of the pin 68 in the hole 12a, actuation of the cable |00 will be almost coincident with the start of the escapement mechanism, whether it be set into motion by the withdrawal of the trip pin 96 or by the disengagement of the detent and cam flange. Yet ii the pin 6 8 is set in the hole '|211 nearly diagonally opposite to '|20'. a much longer time will elapse lbefore the cable is actuated, and effects a measured time interval of actuation after. the start or tl e timing l echanism.

The altitude scale H8 graduated in thousands of feet means that the flange |42 will not disengage the detent H50 atan altitude greater than that forwhichthe index is set. In Fig. 1 the index |1| is set at l5 meaning that. the'parts |40.. and |42 will be in. non-obstructing relation atV altitudes less than 15,000 feet. `If the pin`68.is set in hole. 2a and theV pin 96 removed while the unit'is atan altitude belowl that lfor which theindex |'|f| is set, then the cable |00 will be actuated almost coincident with the removal of the pin 96. If the pin 68 is set in hole '|2n while othe other conditions remain the same,then the cable will be actuated at the end of about thirty.

seconds after the pin 96 is removed. Then,c.Or1-.

sider that the pin 68 is in the time designating hole 12a, and that the release pin 96 is removed at an altitude greater than that indicated by the.

index The cable |00 will be actuated. under those conditions only after the timer-actuator unit has descended to the altitude indicated by the index If the pin 68 is set in time designating hole |211 with the other conditions the same, then the cable will be actuated about thirty seconds after the timer-actuator unit has descended to the level indicated by the index Operation of the timer-actuator in any mode is the same, and when equipped with the additional control by the aneroid unit, gives such control over a load to which it is attached that pern son or parcel may be discharged from an aircraft at very high altitudes with the assurance that the load will reach the earths surface in the best of.

condition. Let it bel assumed that the aneroid unit is set with the index arrow at 15,000 feet and that the timer knob 60 is set at thirty seconds, say in the time designating hole 72u, with.

oi necessity, and the load is permitted to free fall' to a safe altitude before any release mechanism is put into operation.

line or otherwise, but the escapement mechanism is still restrained from operation because of the member 98 engaging the lug 92. pressure experienced at the high altitude the aneroid unit I04will have expanded to dispose the cam ilange |552 in front of the detent |40 which prevents oscillation of the arm |02. As the load descends in the free fall it reaches the 15,000 foot altitude at which the aneroid unit is collapsed. enough topermit the detent |40 to escape theV edge of the cam ange |42, and which permits the member 96 to oscillate away from the lug 92. However, the cable e |00 is not yet actuated. The escapement mechanism starts to operate and permits the driving gear i4 to rotatecounterclockwise carrying with it thepin 03. During that movement the stem 6G supporting the pin 68 moves past the hooked end or the safety lever 40 and beyond the position for the time designating hole 72a to engage the lock arm 34 and cam it out of the notch of the lock disc 30. Immediately that the lock disc 30 is releasedthe remaining energy in the spring` 24 is suddenly expended in rotating the spool 32 clockwise as viewed in Fig. 3, which will actuate the cable |09 by winding it up on the spool.

While the embodiment oi the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted. f

In discharge iromthe. craftthe trip pin 96 may be removed by static.'

Under the low.

i "9 What is `claimed is as follows:

1'.` A timer-actuator for effecting actuation of a "selected device in response to the occurrence of preselected conditions in combination with a selected interval of time, comprising in combination, a spool provided with an actuator cable adapted to be attached to the device to be actuated, a spring power unit selectively operable to drive said spool, `a gear train driven by the power unit, an escapement mechanism regulating the operation of the gear train, and having a stop lug, means including a release pin for `arresting the operation of the escapement mechanism, means for selecting the interval of time in which the gear train will operate after the start of the escapement mechanism before the spool will be driven, and a conditions responsive unit having a member interposed between the stop lug of the escapement mechanism and the release pin to control the start of the escapement mechanism though the release pin has been withdrawn, whereby the selected device is actuated only when the selected time interval has elapsed after the occurrence of the preselected conditions.

2. A timer-actuator for effecting actuation of a selected device in response to the occurrence of preselected conditions in combination with a selected interval of time, comprising in combination, a spool with actuator cable for actuating the selected device, a spring motor for driving the spool in one direction in order to wind up the cable, a gear train with escapement mechanism driven in the opposite direction by said spring motor, means including a release pin and an interposed member for restraining the operation of said escapement mechanism, a lock lever engaging a part of the gear train for restraining the drive of said spool, selective time interval means actuated by the gear train for releasing said lock lever, a barometric unit for actuating said interposed member, and manually controlled means for determining the conditions under which the interposed member will release the escapement means, whereby the lock lever will be released at a predetermined interval after occurrence ofthe determined conditions.

3. A timer-actuator for effecting actuation of a selected device at the end of a selected interval of time after reaching a predetermined altitude in descent, comprising in combination, a cable winding spool for actuating said device, lock means for restraining said spool against winding movement, power means including an escapement for driving said spool, selective interval determining means for releasing the lock means so that the spool may be driven a predetermined interval after the escapement means is set into motion, and means controlling the start of the escapement means including a removable pin and an interposed member, a barometric unit for control of the interposed member, and means for setting the barometric unit to actuate the interposed member when a predetermined altitude of descent has been reached, removal of said pin failing to start the escapement means unless the descent has reached an altitude less than the predetermined altitude.

4. A timer actuator for aerial delivery, a spool and cable adapted to actuate a device, a power unit for driving the spool in response to the occurrence of preselected altitude and time interval conditions, an escapement means for restraining the operation of the power device, selective means for setting the interval of time the escapement means will restrain the power device before the 10 spool is driven, means for controlling the start ofthe escapement means including a removable pin and an oscillating lug interposed between the pin and the escapement means, a pressure responsive bellows controlling the oscillation of said lug, and means for selecting the pressure condition under which the lug will be permitted to oscillate, said lug and pin when in engagement preventing the operation of said escapement an hence the drive of the cable spool. 5. The combination set forth in claim 4l wherein a casing encloses the spool and the pressure responsive bellows and provides a` sight opening over the, bellows for its setting, caps with seal iring removably secured over the interval setting means and the pressure selecting means'to prevent foreign matter interfering vvith'the operation of the timer actuator.

6. A timer actuator for aerial delivery, comprising in combinotion, cable winding spool for actuating a selected device, releasable spool locking means for controlling the cable winding spool, a gear train with escapement means, adapted to release the spool lock, a spring motor operatively coupled between the spool and the gear train, an oscillatable lug engageable with the escapement means to restrain it against operation against the urge of the spring motor, a removable pin for holding the lug against movement, a barometric unit for control of the oscillatable lug when the pin is removed, whereby the escapement means is restrained against operation until a selected altitude of descent is reached, said spring motor then driving the escapement means for a preselected interval of time before releasing the spool lock, and after releasing the spool lock then driving the spool from the gear train as an abutment.

7. The combination set forth in claim 6 wherein a housing provides a mounting plate for enclosure of the spring motor and escapement means, and a cuplike cover encloses the spool locking means and barometric unit, while a single set of hold-down screws secure the housing,

Jmounting plate, barometric unit and cuplike cover in proper assembled relation, and an aperture in said mounting plate through which the oscillatable lug extends to engage the escapement means.

8. The combination set forth in claim 6 wherein the barometric unit comprises a sub-assembly including an adjustable dial and cam flange cooperable with a lever providing the oscillatable lug, and mounting means for the unit disposing the oscillatable lug in interposed relation between the escapement means and the removable pin.

9. The combination set forth in claim 6 wherein the barometric unit comprises a pair of U- shaped brackets with their leg portions in telescoped relation, an exhausted capsule disposed between the brackets and having a central plug mounted for limited rotation in the bridge portion of one of the brackets, a cam ange carried by the capsule and rotatable with the central plug, a sub-base secured to the other of said brackets, a lever providing said oscillatable lug and having a detent engageable with said cam flange of the capsule, and conic pivot means for the lever eliminating lost motion in its oscillation between the cam flange and the escapement means.

10. In a timer-actuator for aerial delivery of loads, having a member to be operated in response to interaction of altitude and time interval measuring means, and a release pin for conditioning 75 th@ timer-actuator to respond to the said inter- 11 action, the combination of a barometric unit having a part interengagng between the release pin and the time interval measuring means for altitude control of the said member, said unit comprising a sub-base, a rectangular framework mounted on the sub-base, an evacuated capsule disposed within the framework, a plug carried by the capsule and having arjournal bearing in said framework, the free end of said capsule being disposed adjacent the sub-base and providing a cam flange, a lever supporting the interengaging part and having pivotal support between the sub-base and frame-work, said lever having a lateral eX- tension engageable behind said cam ange for extreme altitudes, the rotation of said capsule plug in the framework determining the altitude 12 that the cam ange will release the lateralextension vv,of the lever to withdraw the-.interengaging part fromvthe `path of Vthe time interval measuring means.

11. The combination set forth in claim 10 wherein the pivotalsupport for the lever comprises a shaft ending in conc points, a leaf spring secured between the sub-base and framework, and aligned apertures provided by the leaf spring Yand sub-baselreceiving the conic points of the lever shaft, whereby all lost motion of the lever pivot is eliminated.

WILLIAM H..KUNTZ.

'No references cited. 

